Did you check the previous topics?
As a rule of thumb, when it comes to webMethods, Java services shouldn’t be your first choice. Java services are only used when you can’t use the connectors/adapters and flow services, or when performance is a huge concern. I recommend starting with simpler Flow Service development topics. We usually learn something and try to apply that information to a different topic. It usually works but it may also force you to do unnecessary development. Everything is a webservice here, so most of the times you connect a service output to another services input and run it.